Until the mid-nineteenth century, the drugs available from natural sources and existed in form of herbs, plants, roots, vines and fungi. The first synthetic drug was chloral hydrate, it was discovered in 1869 and introduced as a sedative-hypnotics. From 1869 to till now, there has been drastical change in the medicinal field. Rational drug designing leads this field into another level.
Rational drug design often known as drug design, is an incentive process of designing medicines based on the knowledge of biological target, commonly biological target are proteins and nucleic acids. The drug most commonly is an organic small molecule that activates the function of a biomolecule such as protein, which turns the results in a therapeutic benefit to patients. But the process of drug designing is quite complex, costly and time-consuming process, with strategies involving screening of natural products. Generally, the rational drug designing follows a three- step process. Initially, a target (such as a receptor or an enzyme) has to be identified relating to a specific disease state. This target then has to be fully characterized and, finally a molecule must be designed which can binds to it. The molecule which will be designed, must be completely free of toxicity and have good bioavailability.
This last part of the process can take years, since even with good structural information, it is difficult to design a drug with the desired pharmacological activity that will bind specifically to a given target. Rational drug designing can speedily synthesize complex information. Hence, it won’t be wrong to say that rational designing has emerged as boon for medicinal world.